DMARC (Domain-based Message Authentication, Reporting & Conformance) is an email authentication protocol that helps prevent email spoofing and phishing. It builds on SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail) to provide a mechanism for email senders and receivers to improve and monitor the protection of the domain from fraudulent email.
* Understanding DMARC:
* SPF: Defines which IP addresses are allowed to send emails on behalf of a domain.
* DKIM: Provides a way to check that an email claiming to come from a specific domain was indeed authorized by the owner of that domain.
* DMARC: Uses SPF and DKIM to determine the authenticity of an email and specifies what action to take if the email fails the authentication checks.
* Implementing DMARC:
* Create a DMARC policy in your DNS records. This policy can specify to reject, quarantine, or take no action on emails that fail SPF or DKIM checks.
* Example DMARC record: v=DMARC1; p=reject; rua=mailto:[email protected];
* Benefits of DMARC:
* Helps to prevent email spoofing and phishing attacks.
* Provides visibility into email sources through reports.
* Enhances domain reputation by ensuring only legitimate emails are sent from the domain.
* DMARC Record Components:
* v: Version of DMARC.
* p: Policy for handling emails that fail the DMARC check (none, quarantine, reject).
* rua: Reporting URI of aggregate reports.
* ruf: Reporting URI of forensic reports.
* pct: Percentage of messages subjected to filtering.
* Real-World Example:
* A company sets up a DMARC policy with p=reject to ensure that any emails failing SPF or DKIM checks are rejected outright, significantly reducing the risk of phishing attacks using their domain.
* References from Pentesting Literature:
* In "Penetration Testing - A Hands-on Introduction to Hacking," DMARC is mentioned as part of email security protocols to prevent phishing.
* HTB write-ups often highlight the importance of DMARC in securing email communications and preventing spoofing attacks.
Step-by-Step ExplanationReferences:
* Penetration Testing - A Hands-on Introduction to Hacking
* HTB Official Writeups